1. Field of the Invention
This invention relates generally to seismic cable apparatus and more particularly to the adaptation of a protective covering and flow through holder for dual sensor hydrophones splicing spaced along such seismic cables.
2. General Background
Underwater seismic cables with geophone/hydrophones attached thereto are deposited along the sea bed and bottoms of relatively shallow lakes and streams and connected to instrumentation for obtaining seismic data transmitted through the earth's strata in the exploration process for oil and gas. The geophone/hydrophone sensors attached at intervals along the cable serve as listening apparatus for signals being transmitted through the earth. The splice connection for each geophone or hydrophone is often hand made and covered by water proof tape. Each splice leads to a watertight coupling connector extending from a hydrophone or geophone sensor. Rather than allow the geophone or hydrophone sensor to swing free and perhaps become entangled or other wise damaged, various types of flexible holders have been developed and utilized which provide secure attachment of the sensor to the cable adjacent the cable splice point. Such holders either capture the sensor or allow the sensor to be removably inserted without removing the holder from its attachment with the cable. In most cases the holders are molded pliable polymeric units with flow through capability configured in one or more pieces having a slit portion for encompassing the seismic cable and held in place on the cable with plastic tie wraps. These holders fail to provide any protection for the splice joint or the hydrophone or geophone connector and its cable loop becoming entangled, under water or damaged as a result of passing through the cable pay-out and retrieval apparatus. Such holders are limited to only one particular size and type of hydrophone or geophone. The holders previously utilized make no provision for the addition of weights which insure that the hydrophone or geophones remain in near proximity with the earth.